Unsicherer Code

[_m3]

#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <fcntl.h>
#include <limits.h>

/* times are in mikroseconds */
/* #define USLEEPTIME 5000 */
#define LOOPTIME 10000


void usage(const char *progname) {
	fprintf(stderr, "%s: usage\n"
	"%s <tempfile>", progname, progname);
}


int main(int argc, char *argv[]) {
	const char *tempfile;
	struct timespec nano;
	struct stat statbuf;

	char buf[80];
	char filename[PATH_MAX + 100];
	int fd;
	int rc;
	int cnt = 0;
	
	if (argc < 2) {
		usage(argv[0]);
		exit(1);
	}
	
	tempfile = argv[1];
	
	sprintf(filename, "%s.%d.%d.XXXXXX", tempfile, getpid(), cnt++);
	printf("using %s as temporary file\n", filename);
	
	sprintf(buf, "%ld\n", getpid());
	
	for ( ; ; usleep(LOOPTIME) ) {
		/* check for existing tempfile ... */
		if (stat(filename, &statbuf) == 0 || lstat(filename, &statbuf) == 0) {
			sprintf(filename, "%s.%d.%d", tempfile, getpid(), cnt++);
			printf("\ntempfile exists already - retrying with %s\n", filename);
			continue;
		}
		usleep(LOOPTIME);

		/* fd = open(filename, O_CREAT | O_TRUNC | O_RDWR, 0600); */
		memset(filename, '\0',PATH_MAX+100); 
		sprintf(filename, "%s.%d.%d.XXXXXX", tempfile, getpid(), cnt++);
		printf("using %s as temporary file\n", filename);
		fd = mkstemp(filename);
		if (fd == -1) {
			perror("open");
			exit(2);
		}
		printf("The REAL temporary filename is: >%s<\n", filename);

		rc = write(fd, buf, strlen(buf));
		if (rc == -1) {
			perror("write");
			exit(2);
		}
		close(fd);
		unlink(filename);
		printf(".");
		fflush(stdout);
	}

return 0;
}